#include<vector>
#include<iostream>

using namespace std;


int getSum(int a, int b) {
    int t = 1;
    while (t)
    {
        t = a & b;
        a = a ^ b;
        b = t << 1;
    }
    return a;
}

int main()
{
    cout << getSum(13, 28)<< endl;
	return 0;
}